This invention relates to an improved design of vapor-liquid separators of the type generally used in recirculating nuclear steam generators. More specifically, the improved vapor-liquid separator is vertically disposed in an upper portion of a pressure vessel and with a bottom inlet for upward vertical flow of a vapor-liquid mixture, separation of the phases being effected by centrifugal forces. Steam generators utilizing these separator devices are usually vertically oriented and the number of separators, which may exceed one hundred, which can be installed in the upper portion of a pressure vessel is limited by practical considerations including the diameter of the pressure vessel. Because of technological advances and developments in steam and electric power generation, existing separator designs are no longer capable of meeting present-day stringent requirements involving steam quality and steam generator circulation characteristics.